mirror of
https://github.com/triqs/dft_tools
synced 2024-12-26 14:23:38 +01:00
91 lines
3.3 KiB
C++
91 lines
3.3 KiB
C++
|
|
/*******************************************************************************
|
|
*
|
|
* TRIQS: a Toolbox for Research in Interacting Quantum Systems
|
|
*
|
|
* Copyright (C) 2011 by M. Ferrero, O. Parcollet
|
|
*
|
|
* TRIQS is free software: you can redistribute it and/or modify it under the
|
|
* terms of the GNU General Public License as published by the Free Software
|
|
* Foundation, either version 3 of the License, or (at your option) any later
|
|
* version.
|
|
*
|
|
* TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
|
|
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
|
|
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
|
|
* details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along with
|
|
* TRIQS. If not, see <http://www.gnu.org/licenses/>.
|
|
*
|
|
******************************************************************************/
|
|
#ifndef TRIQS_LATTICE_FUNCTORS_H
|
|
#define TRIQS_LATTICE_FUNCTORS_H
|
|
|
|
namespace triqs { namespace lattice_tools {
|
|
|
|
const double pi = acos(-1.0);
|
|
const std::complex<double> I(0,1);
|
|
|
|
template<typename F> struct minus_chech_impl {
|
|
typedef typename F::arg_type arg_type;
|
|
typedef typename F::return_type return_type;
|
|
F f;
|
|
minus_chech_impl(F const & f_):f(f_){}
|
|
brillouin_zone const & bz() const {return f.bz();}
|
|
return_type operator()(arg_type const & x) const { return_type res(f(x)); res *=-1; return res;}
|
|
};
|
|
|
|
namespace result_of { template<typename F> struct minus_chech{ typedef minus_chech_impl<F> type;}; }
|
|
|
|
/**
|
|
* Given f of type F which models FunctionOnBravaisLattice, minus_check(f) :
|
|
* - returns -f(-args)
|
|
* - its type models Function
|
|
*
|
|
*/
|
|
template<typename F> minus_chech_impl<F> minus_chech(F const & f) { return minus_chech_impl<F> (f);}
|
|
|
|
template<typename F >//, typename Enabler = boost::enable_if< Tag::check<Tag::ShortRangeFunctionOnBravaisLattice, F> > >
|
|
class fourier_impl {
|
|
F f;
|
|
brillouin_zone bz_;
|
|
// deduce the return type from decltype(begin()->second)
|
|
public:
|
|
typedef typename non_view_type_if_exists_else_type< decltype(f.begin()->second)>::type return_construct_type;
|
|
typedef typename view_type_if_exists_else_type<return_construct_type>::type return_type;
|
|
typedef K_view_type arg_type;
|
|
|
|
fourier_impl (F f_):f(f_), bz_(f_.lattice()), res(f.n_bands(),f.n_bands()) {}
|
|
|
|
//brillouin_zone const & bz() const { return bz_; }
|
|
|
|
return_type operator()(K_view_type const & k) {
|
|
res()=0;
|
|
for (auto const & pdm : f) { res += pdm.second * exp( 2*pi*I* this->dot_product(k,pdm.first)); }
|
|
return res;
|
|
}
|
|
|
|
protected:
|
|
inline double dot_product(K_view_type const & a, typename F::arg_type const & b) const {
|
|
assert(b.size()>= this->bz_.lattice().dim());
|
|
double r=0; for (size_t i=0; i< this->bz_.lattice().dim();++i) r += a(i) * b[i];
|
|
return r;
|
|
}
|
|
return_construct_type res;
|
|
//typename F::return_construct_type res;
|
|
};
|
|
|
|
/**
|
|
* Given f of type F which models ShortRangeFunctionOnBravaisLattice, Fourier(f) returns
|
|
* - a type that models FunctionOnBravaisLattice
|
|
* - and returns the Fourier transform f(k)
|
|
*/
|
|
template<typename F> fourier_impl<F> Fourier(F f) { return fourier_impl<F> (f);}
|
|
//namespace result_of { template<typename F> struct Fourier { typedef fourier_impl<F> type;}; }
|
|
|
|
}}
|
|
|
|
#endif
|
|
|